Mask data preparation (MDP) is generally the procedure of translating a file containing the intended set of polygons from an integrated circuit layout into set of instructions that a photomask writer can use to generate a physical mask. MDP usually involves mask fracturing where complex polygons are translated into simple shapes (often rectangles and trapezoids) in a format that can be handled by the mask writing hardware.
Multiple patterning is a class of technologies for manufacturing integrated circuits (ICs), developed for photolithography to enhance the density at which components may be placed. An example of multiple patterning is double patterning, where a conventional lithography process is split into two masks or lithographic steps, such that components may be placed more closely together than would be possible if a single mask was used.